Study On Glucose Addition On Water Environmental Control For The Zero-water Exchange Shrimp Culture System

Only 20% ~ 30% of the nutrients in the food is absorbed by fish and shrimp, the remaining nutrients in the form of residual feeds, feces being released into the water environment or deposit into the bottom, the form of inorganic nitrogen accumulation in the water environment, ammonia nitrogen, nitrite nitrogen and other harmful substances concentrations exceeding the standard, resulting in deterioration of water quality, bacterial growth, increase the chance of infection disease of shrimp. The addition of organic carbon source can increase the carbon and nitrogen ratio, promote the growth of heterotrophic bacteria, and convert the ammonia nitrogen and nitrite nitrogen by the assimilation of heterotrophic bacteria, thereby improving water quality. This study respectively uses bio-floc technology in Litopenaeus vannamei zero water exchange greenhouse ponds and indoor culture raceway-type ponds, water environment control by adding glucose, and explores the changes of water quality. Experimental design of this study was as follows, Litopenaeus vannamei was chose as the research object, with glucose as organic carbon source.Part1: Study on glucose addition on water environmental control of the zero-water Exchange Litopenaeus vannamei greenhouse pondsBreeding density and breeding cost of greenhouse ponds was low. there was mud at the bottom of the pool, unable to provide enough water mixing strength to meet the conditions for the bio-floc formation. By adding glucose into greenhouse ponds, it could promote the growth of dissociative heterotrophic bacterial culture, to explore the effect of adding glucose on water environment control parameters of greenhouse ponds. The results showed that throughout the whole process of cultivation average nitrite nitrogen concentration of experimental group was significantly lower than that of control group, respectively were 0.58 mg/L, 0.8 mg/L; nitrate concentration of experimental group was lower than that of the control group; circadian variation range of dissolved oxygen, pH was significantly lower than that of the control group; glucose was added to the water, after seventh days the total amount of bacteria increased by 46.33%, which of experimental group was significantly higher than that of the control group. The addition of glucose has obvious effect on water quality control, and the control of nitrite nitrogen concentration is more obvious, but it does not show the advantage in promoting the improvement of shrimp production.Part2: Study on glucose addition on water environmental control of the zero-water Exchange Litopenaeus vannamei culture raceway-type pondsBy adding glucose, it promoted the formation and growth of bio-floc; By measuring and analysing water quality and microbial diversity,this research would explore effects of glucose addition on water environmental control of indoor zero-water exchange Litopenaeus vannamei culture raceway-type ponds. In the whole experiment process, concentrations of ammonia and nitrite nitrogen rapidly spiked and then decreased, reaching peak concentration of(2.70+0.06) mg/L at 21 days and(10.65+0.075) mg/L at 46 days, respectively. Nitrate concentration stayed at relatively low level of 5.0 mg/L concentration before 45 days, then it continued to rise to(257.72+2.19) mg/L. Concentrations of ammonia and nitrite,however, were relatively stable and maintained low levels of 0.5 mg/L. Alphaproteobacteria, Gammaproteobacteria, Flavobacteria were the common dominant bacteria in the whole process. Abundance of Nitrospira has been in a very low level before 57 days, after the abundance was rose up to 3.1%.